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gruntguru wrote:I think Renault tried to run without a wastegate - using the load bank for the rare ocaision when the turbine was making power that couldn't be sent to the ES (battery full) or the MGUK (Driver throttle demand low). There was no suggestion that they don't have the same self-sustainig mode features as the other PU's. . . or am I missing your point?

Yes, I heard they tried to run the resistor in lieu of a waste gate at the 2014 Tests, and that was what caused them to lose so much running time. I wasn't aware that they had ditched the idea completely, as Renault still don't seem to be able to bypass their turbine.

Mechanical Engineering 101, if you have a pressurised system you need a "fail safe way" to relieve pressure to stop the system destroying itself. In the petroleum industry every pipe and vessel has over pressure protection relief valves, similar to the Waste gate on an FI engine. This can also be achieved with telemetry control, but component failure needs to be fail safe or the results can be catastrophic and extremely dangerous.

My comment on the self-sustaining mode was a guess at where their shortfall is (the numbers seemed to match so it was a neat fit). I just read that they have a major upgrade coming mid-year, so they possibly have not upgraded major components yet, which could also explain the shortfall in power production. It may be in many areas, rather than one...

When y'all say they bipassed a wastegate and went straight to a resistor...what exactly is being referred to as a resistor? Are we talking a literally reverse peltier style system?

And in the petroleum industry, I'm not sure if you're referring to upstream, mid or downstream...but not all failsafes are reliefs. Many are shut in...but I can't imagine that being done for a ln engine system.

gandharva wrote:

No quick fix for Renault piston fault

Cyril Abiteboul is quoted as saying there can be "no solution within the next six weeks".

http://www.auto123.com/en/racing-news/f ... tid=176231

By the sound of things Renault has an incapable, inflexible, or barren engineering team.

PlatinumZealot wrote:

gandharva wrote:

No quick fix for Renault piston fault

Cyril Abiteboul is quoted as saying there can be "no solution within the next six weeks".

http://www.auto123.com/en/racing-news/f ... tid=176231

By the sound of things Renault has an incapable, inflexible, or barren engineering team.

or you have no understanding of how engineering works...?

Does anyone have any insight into the modes of failure of the Renault PU's so far?

In regards to the above, heres is a video briefly explaining a little about F1 piston manufacturing. It is a one of the most complicated metal manufacturing processes performed.

https://www.youtube.com/watch?v=wN8bIyc3JKg

Though Piston problems are not unheard of for Renault, in 1978 with the RS01, they had a multitude of failures usually to do with the pistons. It is a shame for history to repeat itself.

If they have made a design flaw with one of the most critical aspects of an ICE, it really highlights that their single cylinder model and/or full scale test beds are not a real representation of the engine in and F1 car.

Perhaps Mario Ilien's presence at Renault might have complicated things at Vizy, leading to some unfortunate design changes.

sgth0mas wrote:When y'all say they bipassed a wastegate and went straight to a resistor...what exactly is being referred to as a resistor? Are we talking a literally reverse peltier style system?

And in the petroleum industry, I'm not sure if you're referring to upstream, mid or downstream...but not all failsafes are reliefs. Many are shut in...but I can't imagine that being done for a ln engine system.

They didn't bypass a wastegate, they simply didn't have one fitted - relying on the MGUH to slow the turbocharger and limit the boost. Problem is the MGUH generates electricity in this mode and if the battery is full and the driver doesn't want any power to the MGUK at that moment, the spare electricity (energy) has to go somewhere. The simplest solution is to convert it to heat using a resistive heating element (Google "load bank" or more details.)

Charlatan wrote:Perhaps Mario Ilien's presence at Renault might have complicated things at Vizy, leading to some unfortunate design changes.

It's much more likely Mario helped find the problem.

i wonder how much control red bull has over the PU mapping? are they trying to do something Renault didn't test on a dyno?

Afaik the new cylinder head (full design) designed by Illien is not yet ready for testbench before week 21.

In the overall scheme of mechanical engineering, I don't think it is "one of the most complicated metal mfg processes" but I do think the design/analysis process must be pretty tricky.

You'd normally expect a serious failure mode to be picked up on the dyno.

But this does not look like a normal situation.

So how many Renault PU's have gone up in smoke now?

I saw on the news (havent watched the race yet) Daniel's blow up just as he crossed the finish line!

I was wondering if there is any analysis getting around, comparing lap times for a given car/driver combo in 2015 vs 2014? Of particular interest would be Ham, Ros, Rai, RIc. This would surely show which teams have made progress?

gruntguru wrote:

sgth0mas wrote:When y'all say they bipassed a wastegate and went straight to a resistor...what exactly is being referred to as a resistor? Are we talking a literally reverse peltier style system?

And in the petroleum industry, I'm not sure if you're referring to upstream, mid or downstream...but not all failsafes are reliefs. Many are shut in...but I can't imagine that being done for a ln engine system.

They didn't bypass a wastegate, they simply didn't have one fitted - relying on the MGUH to slow the turbocharger and limit the boost. Problem is the MGUH generates electricity in this mode and if the battery is full and the driver doesn't want any power to the MGUK at that moment, the spare electricity (energy) has to go somewhere. The simplest solution is to convert it to heat using a resistive heating element (Google "load bank" or more details.)

It is better to use all the energy the mgu-h to the mgu-k and then to use less power from the ICE hence reducing fuel consumption. This can be managed by the software in the control unit

I wonder how "political" Ricardo's blow-up on the finish line was... Listening to RedBullRacing for the last few months, they are a bit nasty.

It just feels a bit too perfect to be a coincidence